1. Field of the Invention
The present invention relates to framing systems for supporting glazing elements over a substrate, more particularly to a framing system designed for attachment over an existing glazing system or structural framework.
2. Brief Description of the Prior Art
A trend has begun in the glazing industry wherein glazing systems, which include frames supporting glazing elements for windows, skylights, curtainwalls, etc., are being reinforced with a secondary overlaying glazing system. These extra protective systems are needed to resist damage from flying debris and high pressure differentials caused by inclement weather. However, unique problems are encountered in the installation of a secondary glazing system over an existing framing system. For example, the frames of the secondary system must be assembled and fastened such that the fasteners do not contact and break the glazing elements (e. g., glass) of the underlying system. Additionally, the width of the individual frame members of the secondary system need to be minimized so as not to unduly restrict the line of sight. These and other problems arise which are particular to the design and installation of a secondary glazing system.
An object of the present invention is to provide a framing system for use in a primary or secondary glazing system which addresses the problems associated with a secondary glazing system. Another object of the present invention is to provide a framing system made up of a plurality of frame members which overlap with adjacent frame members. A further object of the present invention is to provide a framing system which is easily installed over a metal tubing or wood structural substrate as well as over an existing glazing system. Another object of the present invention is to provide a secondary glazing system which will straddle the fasteners of the original glazing system over which it is applied to minimize the thickness of the secondary glazing system. Another object of the present invention is to provide a framing system with concealed fasteners.